FIELD OF THE INVENTION
Implementations of various technologies described herein generally relate to the access of subsea wells with tools allowing evaluation and intervention services on subsea wells, and more particularly to a method of conveying such evaluation and intervention tools to a subsea well.
The following descriptions and examples are not admitted to be prior art by virtue of their inclusion within this section.
Subsea well interventions may be performed for various reasons. For example, an operator may observe a drop in production or some other problem in the subsea well. In response, the operator may perform an intervention operation, which may involve running a monitoring tool into the subsea well to identify the problem. Depending on the type of problem encountered, the intervention may further include shutting in one or more zones, pumping a well treatment into a well, lowering tools to actuate downhole devices (e.g., valves), and so forth.
Conventionally, to perform subsea intervention, the operator must deploy a rig (such as a semi-submersible rig) or a vessel, as well as a marine riser, which is a large diameter tubing that extends from the rig or vessel to the subsea wellhead equipment. Performing intervention operations with large vessels and heavy equipment such as marine riser equipment is typically time consuming, labor intensive, and expensive. As a result, intervention is only performed when economics/risks look very favorable, and in other cases the well performance is simply accepted without intervention. As a consequence, subsea wells typically produce less and for a shorter duration than equivalent platform wells.
In addition, initial completions of subsea wells are very costly, since many subsea well operators try to predict future needs of the subsea wells by installing expensive completion equipment that would enable the subsea wells to fulfill these potential needs without a well intervention operation. However, since the reservoir description and its dynamic behavior are typically deciphered and understood better over time, it is likely that some anticipated future needs might not materialize and some unexpected ones might appear. In the absence of an intervention method that may be deployed at a reasonable risk and cost, many subsea well operators resort to install these expensive equipment, and resign to accept the consequences of the well's performance without further intervention.
Therefore, a need continues to exist for less costly and more convenient diagnosis (evaluation) and intervention solutions for subsea wells.
Described herein are implementations of various technologies for a method for at least one of evaluating and intervening in a subsea well. In one implementation, the method includes providing a pipeline connecting a platform to the subsea well, coupling a locomotion module with one or more tools, activating the locomotion module to convey the one or more tools from the platform to the subsea well through the pipeline, and using the one or more tool to perform at least one of an evaluation operation and an intervention operation on the subsea well.
In another implementation, the method includes coupling a tractor with one or more tools, activating the tractor to convey the one or more tools from an offshore platform to the subsea well through a pipeline connecting the subsea well with the offshore platform and performing at least one of an evaluation operation and an intervention operation on the subsea well.
- BRIEF DESCRIPTION OF THE DRAWINGS
The claimed subject matter is not limited to implementations that solve any or all of the noted disadvantages. Further, the summary section is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description section. The summary section is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
FIGS. 1A-1B illustrate schematic diagrams of a subsea well intervention system in accordance with implementations of various technologies described herein.
FIG. 2 illustrates a CPU module for use with the subsea well intervention system of FIGS. 1A-1B in accordance with implementations of various technologies described herein.
- DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
FIG. 3 illustrates a schematic diagram of a pipeline in accordance with implementations of various technologies described herein.
FIG. 1A illustrates a subsea well intervention system 100 in accordance with implementations of various technologies described herein. In one implementation, the subsea well intervention system 100 is conveyed from a platform 10 to a wellhead 20 through a pipeline 30, which connects the platform 10 to the wellhead 20. The platform 10 may be one that is coupled to the sea floor or one that is floating on the surface of the sea, such as a spar. Accordingly, by using implementations of various technologies described herein, a subsea well may be accessed without the use of a rig or a vessel, thereby reducing the overall cost of subsea well intervention. This access allows a diagnosis/evaluation of the well production/injection status or problems, and provides the ability to manipulate the well completion and/or treat the formation to address any production or injection issues without the use of costly subsea intervention vessels.
Although various implementations are described herein with reference to one wellhead, it should be understood that some implementations may include more than one wellhead. In such implementations, the pipeline 30 may include several junctions allowing it to be connected to multiple wellheads. Each wellhead may be associated with a tag, e.g., an RFID tag, for identification by a CPU module (described in detail below) of the intervention system 100.
The pipeline 30 may be configured to establish fluid and data communication between the platform 10 and the wellhead 20. Further, the pipeline 30 may include various types of conduits, such as hydraulic control lines, flow lines, electrical control lines, production pipes and the like.
The wellhead 20 is disposed on the sea floor 90 above a subsea well 40, which includes a wellbore 70 that may be lined with a casing or liner 50. A tubing 60, such as a production tubing, may be positioned inside the wellbore 70. A packer 80 may be used to isolate an annulus region 85 between the tubing 60 and the casing 50 from the rest of the wellbore 70. Note that although the figures show a vertical well, embodiments of the invention apply to deviated and extended reach wells as well. In addition, although various implementations of the subsea well intervention system are described with reference to one subsea well, it should be understood that in some implementations the subsea well intervention system may be used with any number of subsea wells.
During production, well fluids may be delivered through the tubing 60, the wellhead 20 and the pipeline 30 to the platform 10. However, over the life of the subsea well 40, production (or injection) may drop and/or experience other anomalies, which may necessitate an intervention. As such, the subsea well intervention system 100 may include a locomotion module, for example a tool based locomotion enabler, such as a tractor 110, or a pipeline based locomotion enabler, such as electromagnets, to convey the intervention system 100.
In one implementation, the intervention system includes the tractor 110, which is coupled to a communication module 140 and to one or more sensors 120 capable of performing an evaluation operation on the well. For example, the sensors 120 may be configured to measure various well attributes, such as well pressure, well temperature, production flow rate of the different effluents (e.g., oil, gas, water), formation characteristics and the like. As such, the sensors 120 may include emitters and receivers (e.g., acoustic, nuclear and resistivity electrodes) or any other typical well logging device (e.g., pressure transducers, gravity transducers, light transducers and other sensing devices.)
In another implementation, the intervention system 100 includes the tractor 110, which is coupled to the communication module 140 and one or more intervention tools 130 capable of performing an intervention operation on the well. For example, the intervention tools 130 may be configured to perform various intervention operations, such as adjust sliding sleeves, set plugs, perforate, repair screen, inject specialty fluids, cut, and/or weld, among various other intervention operations. The communication module 140 may facilitate data communication between the sensors 120 and/or the intervention tools 130 and a well operator or a controller 105 located on the platform 10 or some other surface location.
In yet another implementation, the intervention system 100 includes the tractor 110, which is connected to the communication module 140, the one or more sensors 120, and the one or more intervention tools 130, such that both evaluation and intervention operations may be performed by the same assembly. As such, depending on the embodiment used, the intervention system 100 is capable of performing an evaluation operation, an intervention operation, or both an evaluation and an intervention operation. Also, in any of the embodiments described above, the subsea well intervention system 100 may also include a power module (not shown) for supplying power to any or all of the intervention system components.
As shown in FIG. 1A, in one implementation, the subsea well intervention system 100 may further include a wireline 150 coupled to a wireline unit 160, which is disposed on the platform 10. The wireline 150 may be coupled to the communication module 140. In this implementation, a lubricator and other wireline equipment may be used to facilitate the wireline operations. In lieu of a wireline, the communication module 140 may be coupled to any pipe that may deploy the tools downhole, e.g., coiled tubing or any other type of tubing.
In another implementation, the communication module 140 may be configured to communicate with the controller 105 wirelessly. As such, the subsea well intervention system 100 may further include one or more repeaters 155 disposed along the pipeline 30, as shown in FIG. 1B. The repeaters 155 are configured to transmit signals between the communication module 140 and the controller 105.
In any of the embodiments discussed above, the intervention system 100 may further include a CPU module 200. In such embodiments, the CPU module 200 controls any or all of the intervention system components. The CPU module 200 may receive operational signals from the controller 105, or the CPU module 200 may be fully automated to perform evaluation and/or intervention operations without receiving any communication from the controller 105 at the surface.
As shown in FIG. 2, in one embodiment the CPU unit 200 includes a CPU 210, a system memory 220, a storage device 240, and a system bus 230 that couples the CPU 210 with both the system memory 220 and the storage device 240. The CPU 210 may be configured to process various program modules stored inside the storage device 240, some of which may be discussed in more detail in the following paragraphs. Alternatively, the CPU module may be incorporated into one of the other intervention system components, such as the locomotion module, or any other appropriate module on the intervention system 100.
In the depicted embodiment of the CPU module 200, the system memory 220 may include a random access memory (RAM) 225 and a read-only memory (ROM) 228. A basic input/output system containing the basic routines that help to transfer information between components within the computer, such as during startup, may be stored in the ROM 228.
The storage device 240 may include an operating system 245 (O/S) and program modules executable by the CPU 210. The operating system 245 may be configured to control the operation of the intervention system components. The operating system 245 may be Windows® XP, Mac OS® X, or Unix-variants, such as Linux® and BSD®, and other appropriate systems. In one implementation, the storage device 240 may include an application 246 for controlling the operations of the sensors 120 and/or the intervention tools 130.
The storage device 240 and its associated computer-readable media may be configured to provide non-volatile storage for the CPU module 200. Those skilled in the art will appreciate that computer-readable media may refer to any other appropriate media. For example, computer-readable media may include computer storage media and communication media.
Computer storage media includes volatile and non-volatile, and removable and non-removable media implemented in any method or technology for storage of information such as computer-readable instructions, data structures, program modules or other data. Computer storage media further includes, but is not limited to, RAM, ROM, erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other solid state memory technology, CD-ROM, digital versatile disks (DVD), or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information.
In operation, the subsea well 40 may be accessed by conveying the subsea well intervention system 100 through the pipeline 30 by use of the locomotion module, such as a tractor 110. In one implementation, the subsea well 40 may be accessed or intervened by the tractor 110, the sensors 120, the intervention tools 130, the communication module 140 and the wireline 150. In this implementation, one or more wireline equipment, such as a lubricator, may be used to facilitate the wireline operations.
In another implementation, the subsea well 40 may be accessed or intervened by the tractor 110, the sensors 120, the intervention tools 130, the communication module 140 and a set of repeaters 155. In this implementation, the communication module 140 and the repeaters 155 enable the sensors 120 and the tools 130 to communicate wirelessly with the controller 105 on the platform 10. In yet another implementation, the subsea well 40 may be accessed or intervened by the tractor 110, the sensors 120 and the intervention tools 130 and the CPU module 200. In this implementation, the intervention system 100 may be fully automated.
In one embodiment a lubricator is connected between the platform 10 and the pipeline 30, with a valve connecting the lubricator to the pipeline 30. In such an embodiment, intervention tools may be conveyed to the well 40 by inserting the tools into the lubricator. After deployment in the lubricator, pressure is equilibrated and the valve is opened to allow access to the pipeline 30. The tractor 110 may then be activated to convey the sensors 120 and/or the intervention tools 130 to the well 40.
In one embodiment, any or all of the intervention system components may be adjustable. For example, any or all of the intervention system components may be articulated to adjust the angular orientation thereof, and/or be linearly moved to adjust the linear distance between adjacent components. Such adjustments facilitate movement of the intervention system 100 through the pipeline 30 and can be accomplished for example by incorporating a spoolable cable between adjacent components. Although the adjustment of intervention system components or modules has been described, similar adjustment(s) can additionally or alternatively be made in a similar manner to the sensors 120 in embodiments where the intervention system 100 includes sensors 120.
FIG. 3 illustrates a schematic diagram of an alternative embodiment of a pipeline 300 for connecting the platform 10 (shown in FIGS. 1A-1B) to the wellhead 20. Other components of the system described above with respect to FIGS. 1A-2 are unchanged and are therefore not repeated with respect to FIG. 3 to avoid duplicity. As shown, in one implementation the pipeline 300 includes a bypass line 310 coupled to the wellhead 20. The bypass line 310 includes a first portion 330 and a second portion 340, which is at an obtuse angle a with respect to the production tubing 60 in the depicted embodiment. In one implementation, the second portion 340 may be disposed substantially in line with the production tubing 60. In this manner, the bypass line 310 is configured to provide a pathway for the tractor 110 and the set of tools coupled thereto to more easily enter the wellhead 20, than is possible with a typical 90 degree connection between the pipeline and the production tubing.
Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.